US 5,801,083 A · Use of polymer spacers for the fabrication of shallow trench isolation regions with rounded top corners

Abstract

A method for forming insulator filled, shallow trench isolation regions, with rounded corners, has been developed. The process features the use of a polymer coated opening, in an insulator layer, used as a mask to define the shallow trench region in silicon. After completion of the shallow trench formation the polymer spacers are removed, exposing a region of unetched semiconductor, that had been protected by the polymer spacers, during the shallow trench dry etching procedure. The sharp corner, at the intersection between the shallow trench and the unetched region of semiconductor, is then converted to a rounded corner, via thermal oxidation of exposed silicon surfaces. The polymer spacers also eliminate the top corner wraparound.

Claims16

Dependent claims

A method for creating an insulator filled, shallow trench isolation region, in a semiconductor substrate, comprising the steps of:

depositing a first insulator layer on said semiconductor substrate;
forming an opening in said first insulator layer, exposing said semiconductor substrate;
forming polymer spacers on the sides of said opening, creating a polymer coated opening;
creating a shallow trench in said semiconductor substrate, in a region exposed in said polymer coated opening;
removing said polymer spacers, exposing a region of unetched semiconductor substrate, located between said first insulator layer and said shallow trench;
growing a silicon dioxide layer on exposed silicon surfaces of said shallow trench, and on said region of unetched semiconductor substrate;
and
filling said shallow trench with a second insulator layer.

5 more elements

A method for forming an insulator filled, shallow trench isolation region, with rounded corners, in a semiconductor substrate, comprising the steps of:

depositing a composite insulator layer, on said semiconductor substrate;
forming a photoresist shape, with a first opening, on said composite insulator layer;
anisotropic etching of said composite insulator layer, using said photoresist shape as a mask, extending said first opening in said photoresist shape, to said composite insulator layer;
forming polymer spacers on the sides of said first opening in said photoresist shape, and on the sides of said first opening in said composite insulator layer, creating a polymer coated opening;
dry etching of said semiconductor substrate, exposed in polymer coated opening, creating shallow trench regions;
removal of said photoresist shape, and of said polymer spacers, exposing a region of unetched semiconductor substrate, between said shallow trench and said composite insulator layer, and exposing a sharp corner at the intersection of said shallow trench and said region of unetched semiconductor substrate;
growing a silicon oxide layer on exposed surfaces of said shallow trench, and on the exposed surface of said region of unetched semiconductor substrate, converting said sharp corner, to a rounded corner, at intersection of said shallow trench and said region of unetched semiconductor substrate;
depositing an insulator layer on top surface of said composite insulator layer, completely filling shallow trench;
and
removing said insulator layer from the top surface of said composite insulator layer, resulting in said insulator filled, shallow trench, with rounded corners.

7 more elements

Dependencies are inferred from the claim text.

Use of polymer spacers for the fabrication of shallow trench isolation regions with rounded top corners

Life of this patent

Use of polymer spacers for the fabrication of shallow trench isolation regions with rounded top corners

Life of this patent

Abstract

Claims16